1. Field of the Invention
The present invention relates to the base, drum, and drum mounting unit of a magnetic recording reproducing apparatus in which the drum is mounted in a magnetic recording reproducing apparatus such as video tape recorder or the like.
2. Related Art Statement
In a VTR (video tape recorder), a front loading system is sometimes adopted in which a tape cassette is approximately horizontally loaded into a deck from the front of the deck. In the front loading system, when a tape cassette is inserted into a cassette holder from the front of the deck, the cassette holder moves to a tape loading unit and loads the tape cassette into the tape loading unit. When the tape cassette is set in a predetermined position, a tape in the tape cassette is pulled out by the tape loading unit. The tape loading unit pulls out a tape in a cassette approximately parallel to the surface of a base and winds the tape around a drum.
In a helical scan system, recording and reproducing are performed by obliquely tracing the tape with a magnetic head provided on the drum and hence the drum is mounted on the base at a predetermined angle with respect to the base. The tape loading unit hooks the tape on a pair of tape pulling-out members (hereinafter referred to as xe2x80x9csliderxe2x80x9d) and pulls out the tape from the tape cassette and moves these sliders to the vicinity of the other end of the drum mounted at the predetermined angle to reel the tape around the drum.
In order to mount the drum to a base at the predetermined angle with respect to the surface of the base, a tilt stand is formed in the same shape and same size as the bottom of the drum and is mounted on the base and the drum is fixed with screws at several points of the end portion of the tilt stand. In this way, the drum is tilted at a predetermined angle with respect to the surface of the base.
A normal-feed press process is adopted for machining the base. The normal-feed press process is also used for various openings and the tilt stand. However, the drum needs to be mounted with extremely high accuracy of the order of several micrometers. In order to enable the drum to be mounted with extremely high accuracy, a screw hole for regulating the position of the drum of the tilt stand portion and a receiving surface thereof for regulating the height of the drum need to be worked by a press process different from the normal-feed press process used for the other portions of the base. That is, those portions need to be press-worked in the state where the base is tilted in correspondence with the tilt angle of the tilt stand.
This presents a problem that the number of processes for machining the base increases. Here, it is also thought that the tilt stand is formed separately by a die casting method, but in this case, the number of processes further increases and the number of parts also increases.
Further, since a structure is adopted in which the drum is fixed with screws at several positions of the brim of the tilt stand, the drum mounting surface of the tilt stand is relatively large in size and the height of the tilt stand is also large. That is, the tilt stand needs to be subjected to a large bending by a press machine, which results in increasing the load of the press machine. Also, the area of an opening made in the base becomes large. This presents a problem that the strength of the base decreases.
Still further, a lead for guiding the tape is formed on the peripheral surface of the drum. There is a possibility that the lead is deformed when the drum is mounted on the tilt stand with screws. Therefore, in order to keep the linearity of the lead with sufficient accuracy, the surface of the tilt stand needs to be worked with extremely high accuracy, but it is very difficult to work the surface of the tilt stand with high accuracy.
As described above, in order to mount the drum with high accuracy, the tilt stand, on which the drum is mounted, needs to be formed by a press process different from the normal-feed press process, which presents a problem that the number of processes increases. Further, this presents problems that the load of the press machine increases and that the strength of the base decreases. Still further, in order to keep the linearity of the lead with sufficient accuracy, the accuracy of the surface of the tilt stand needs to be improved, which presents a problem that it is very difficult to work the surface of the tilt stand with high accuracy.
An object of the present invention is to provide the base, drum, and drum mounting unit of a magnetic recording reproducing apparatus which can be made by a decreased number of processes by forming a tilt stand only by one normal-feed press process.
Another object of the present invention is to provide the base, drum, and drum mounting unit of a magnetic recording reproducing apparatus which can prevent a decrease in the mounting accuracy of the drum even if the drum is mounted on a tilt stand formed only by one normal-feed press process.
Further another object of the present invention is to provide the base, drum, and drum mounting unit of a magnetic recording reproducing apparatus which can prevent a decrease in the accuracy of the linearity of a lead by mounting the drum in the vicinity of the shaft of the drum.
Still further another object of the present invention is to provide the base, drum, and drum mounting unit of a magnetic recording reproducing apparatus which can reduce the load of the press machine by forming a tilt stand only by one normal-feed press process.
Still further another object of the present invention is to provide the base, drum, and drum mounting unit of a magnetic recording reproducing apparatus which can be increased in strength by reducing the size of an opening made in the tilt stand.
A base of a magnetic recording reproducing apparatus in accordance with the present invention includes a tilt stand having a drum mounting surface tilted with respect to a plane and not less than one mounting hole for mounting a drum which is punched in the mounting surface in the direction perpendicular to the plane.
A base of a magnetic recording reproducing apparatus in accordance with the present invention includes a tilt stand having a mounting surface tilted to mount a drum thereon and a shaft mounting hole which is formed in the mounting surface and into which a shaft of the drum is inserted to regulate the position of the drum on the mounting surface.
Further, a base of a magnetic recording reproducing apparatus in accordance with the present invention includes a tilt stand having a mounting surface tilted to mount a drum thereon, a shaft mounting hole which is formed in the mounting surface and into which a shaft of the drum is inserted, and not less than one mounting hole which is formed in the range of a diameter smaller than the diameter of the drum from the shaft mounting hole to mount the drum thereon.
Further, a base of a magnetic recording reproducing apparatus in accordance with the present invention includes a tilt stand having a mounting surface tilted to mount a drum thereon, a shaft mounting hole which is formed in the mounting surface and into which a shaft of the drum is inserted, and an opening which is formed in the mounting surface at a position lower than the shaft mounting hole and through which a connector fixed to the drum is exposed to the reverse surface of the base.
Further, a base of a magnetic recording reproducing apparatus in accordance with the present invention includes a tilt stand having a mounting surface tilted to mount a drum thereon, and a cut and bent portion which is formed by cutting and bending the base and retains the drum mounted on the tilt stand to provisionally fix the drum.
Further, a drum of a magnetic recording reproducing apparatus in accordance with the present invention includes a cylindrical fixing member for supporting a cylindrical rotary member provided with a head for tracing a tape on the peripheral surface thereof, a shaft being a rotational center of the cylindrical rotary member and projecting from the bottom of the cylindrical fixing member and being inserted into the first mounting hole formed in the mounting surface of a base to position the drum with respect to the mounting surface, and a fixing portion formed on the bottom of the cylindrical fixing member and fixed to the mounting surface by the use of the second mounting hole formed in the mounting surface to position the drum in the angular direction with respect to the mounting surface of the cylindrical fixing member.
Further, a drum of a magnetic recording reproducing apparatus in accordance with the preset invention includes a retaining portion having a shape corresponding to a cut and bent portion formed on a tilt stand of a case by cutting and bending the base, wherein the drum is provisionally mounted on the tilt stand by making the retaining portion retain the cut and bent portion.
Further, a drum mounting unit of a magnetic recording reproducing apparatus in accordance with the present invention includes a tilt stand formed on a base and having a mounting surface tilted with respect to a plane to mount a drum thereon, the first mounting hole and the second mounting hole which are punched in the mounting surface in a vertical direction with respect to the plane, a shaft which is a rotational center of the drum and a part of which projects from the bottom of the drum and is inserted into the first mounting hole to position the drum with respect to the tilt of the drum, and a fixing portion which is formed on the bottom of the drum and is fixed to the mounting surface by the use of the second mounting hole to position the drum in the angular direction with respect to the mounting surface.
The other features and advantages of the present invention will be made sufficiently clear by the following description.